Climbing stairs is known to place stresses on the knee joints which aggravate knee injuries or arthritic knee deterioration, usually resulting in immediate or delayed pain. People with such knee conditions are advised not to climb or descend stairs. Since most homes and buildings have more than one floor level, stairs are a common feature of inhabited buildings. Nursing homes, on the other hand, are often designed to have only a single floor level to eliminate stairs for their senior residents who are of the age most likely to have knee joint injuries and/or arthritis.
The alternative to climbing or descending stairs in a home or building in which one resides or works is to ride an elevator, escalator, chair lift, or scoot on one's bottom so as to minimize the knee bending while supporting body weight, which is required for climbing or descending stairs. It is known that the greater the angle the knee joint bends when body weight is supported, the greater the stress on the knee joint. Since climbing and descending stairs applies full body weight to one knee joint at a time, such activity places even more stress on the knees than just standing and bending both knees simultaneously. Typical home and building staircases are designed with a rise between steps of 7 to 9 inches and an overall angle of incline ranging from 35.degree. to 45.degree.. When a person climbs such stairs one at a time, the average adult knee joint bends from 50.degree. to 70.degree. as measured from an axis through an ankle joint and corresponding knee joint.
Providing stairs with a gentler angle of incline and/or reduced elevation between steps would reduce the angle of knee bend and therefore the stress placed on knee joints. However, such reductions would increase the space needed for stairs and make stair climbing inconvenient for the majority of people who have no knee joint problems. Furthermore, it would be nearly impossible to convert all the existing staircases to have significantly lower angles of incline or a significantly greater number of steps.
What has been missing is a wearable device which reduces the angle of knee bend when climbing or descending stairs to an angle such that the knee stress is reduced to an acceptable level that minimizes knee joint strain or pain.